Serenoa repens (saw palmetto) and Pygeum africanum appear to have modest benefit on the pathophysiology of established benign prostatic hyperplasia (BPH) but even more importantly these agents may affect the pathogenesis of the progressive disease process. Almost every individual study, systematic review and meta-analysis report analyzing the effect of these phytotherapeutic agents on BPH have come to the same conclusion: further research is needed to determine the long term safety and effectiveness and ability to prevent complications associated with progressive BPH. The primary objective of this study is to determine if serenoa repens or pygeum africanum delays or prevents clinical progression of benign prostatic hyperplasia compared to placebo treatment. Secondary objectives will compare relative efficacy of these two treatments and also determine whether either of these agents ameliorate symptoms of BPH, improve BPH specific quality of life, improve maximum flow rate and reduce residual urine in men with BPH. Men with mild to moderate symptoms of BPH who do not desire or require immediate medical or surgical treatment will be randomized to placebo, serenoa repens or pygeum africanum after placebo run in and will be followed for disease progression for a minimum of four years. Progression will be defined as an increase in AUA symptom score of 4 or more points from baseline, or occurrence of any of the following complications of BPH;acute urinary retention, incontinence, obstructive uropathy (measured as increased creatinine) or BPH related urinary tract infection. The Canadian BPH Research Group (Canadian CETC) have demonstrated experience and expertise in designing and implementing multi-center clinical trials in BPH and are the most successful research group in Canada in recruiting patients to multi-center BPH trials. The principal investigator has been a successful and effective collaborator in studies funded by NIH-NIDDK. The members of this group have demonstrated their willingness and ability to work in an effective and congenial manner in collaborative international multi-center studies including NIH sponsored collaborative groups. The Canadian BPH study group would be a valuable partner in the proposed NIH phytotherapeutic BPH prevention trial.